Multiple shear pin



@ct A45, ma H. A. w. W000 3 9 MULTI PLE SHEAR P IN Filed Nov. 25, 1928 r/e zlr 762741494 72129 7503 n mph- Patented Oct. 14, 1930 UNITED STATES PATENT OFFICE m! A. WISE WOOD, NEW YORK, N. Y., ASSIGNOB TO WOOD zmwsrarm nom- EBY CORPORATION, 01' NEW YORK, N. Y., COBZOBATION OI VIRGINIA I'UDTHLE sum rm Application filed November 23, 1828. Serial No. 821,885.

' This invention relates to shear pins for any kind of machinery, such pins be1ng adapted to connect two elements, as for example, two rotating shafts, to shear or break when any undue strain is encountered, thus locating the break at a predetermined point and prevent the breaking of other arts of the machine. The shear pm ordinari y after being broken, of course, is taken out and replaced at a small ex ense, but sometimes this requires an apprecia 1e amount of time.

This invention relates to a shear pin which is adapted to be broken in a plurality of places at successive times and to be replaced l5 merely by forcing it along longitudinally until a second oove or weak spot comes in the plane or division between the two elements which it connects. v Reference is to be had to the accompanying drawings in which Fig. 1 is a longitudinal sectional view of two shafts connected by a shear pin, constructed in accordance with-this invention, and 2 Fig. 2 is an end view.

I have shown the invention as applied for connecting two shafts 10 and 11. Each shaft has a head 12. These heads abut against each other but have a space or recess 13 between them inside. They are bored at one point and a shear pin 15 introduced so that the power for driving one shaft b the other will all be transmitted through t is shear in.

This pin is provided with a p urality of circumferential grooves 16 or otherwise weakened in a plurahty of planes. It is shown in its original position.

The pin is provided with a holder 17 in the space 13 which consists of a ring resting in one groove 16 and preventing thedisplacement of the pin. p

I have also shown a ball 18 and spring 19 arrangement engaging another groove and rforming two functions. It assists in holdmg the pin position ordinarily and in fact, it-can be substltuted for the holder 17 for that purpose and that can be omitted, but, of course, it is not a positive means for holding it. It also serves to hold the pin in place after 5 it has been broken at the groove 16.

'tions therethrough, o

In the use of the device the pin, being placed in the position shown, will be broken 1f enough resistance is encountered. This break occurs in the first groove 16, the one that is located in the recess 13. This, as in other shear pins, ensures that the breakage w1ll occur here where it can be repaired in a very s mple manner instead of in some other point in the machine and thus it protects the rest of the machine.

After the breakage occurs, the two shafts are brought around together so that the two holes through them register and then the pin 15 is forced in until the second groove 16 comes in the recess 13. At this. time the holder 17 enters this groove and tends to hold the pin in position and the ball 18 will enter the next groove if there is another.

The pin can be pushed in easily because neither of the holding means is positive. The unused part of the pin will be prevented from falling out by the spring'and ball construction when the pin is broken at another point.

This constitutes a very simple means for providing for the renewal of the connection and avoi s the necessity of removing a part of the pin from each of the two heads 12, which sometimes causes some trouble and delay.

Althou h I have illustrated and described only one orm of the invention I am aware of the fact that modifications can be made therein by any person skilled in the art without departing from the scope of the invention as expressed in the claims. Therefore I do not wish to be limited in this respect but what I do claim is 1. The combination with a pair of movable elements having registering perforaa shear pin located in said perforations and having a weakened area located at the plane of division between the two elements, said shear in having a second weakened area loca within the at body of one of said elements and yielding means engaging the second groove for holding the P111 in place after the end is broken.

2. The combination with two movable elements each having a perforation, of a shear mo .pin extending through both perforations and having a series of circumferential grooves s aced apart, any one of which can e locate at the line of division between the two elements, and a holding means located between said two elements for engaging in the groove which is in position to be broken.

3. The combination with two movable elem ments each having a perforation, of a shear pin extending through both perforations and having a series of circumferential grooves spaced apart, any one of which can e located at the line of division between I the two elements, a holding ring located between said two elements for enga ing in the groove which is in position to e broken and a ball and spring located in one of said elements and engaging another groove so in the pin to help ho d the pin in position to perform its function and to hold the pin in place when the end is broken off.

4. The combination with two movable ele- 4 ments each havin a perforation, of a shear a pin extending through both perforations and having a series of circumferential grooves spaced apart, any one of which can e located at the line of division between the two elements, and a ball and spring 10- cated in one of said elements and engaging another groove in the pin to hold the pin in position to perform its function and to hold the pin in place when the end is broken ofi'.

In testimony whereof I have hereunto affixed my slgnature.

HENRY A. WISE woon. 

